A state-commissioned report, released Thursday, has concluded that California must rely on natural gas stored underground for decades to come to meet the state's energy needs.

The California Council on Science and Technology, an independent nonpartisan organization, assessed the long-term viability of underground gas storage in the state at the request of Gov. Jerry Brown and the state Legislature.

Although the report takes a broad scientific look at gas storage, it also addressed the shortcomings of the operations at the Aliso Canyon natural gas storage facility operated by Southern California Gas Co. A massive gas leak at Aliso Canyon forced thousands of residents to evacuate in 2015.

The report said gas had been injected and withdrawn through the center tubing of the well as well as the area between the tubing and the well's outer casing. That practice leaves a well with no protection against a leak if the casing deteriorates or ruptures. New regulations now require gas to be injected or withdrawn only through the well's center tubing, leaving the space between the tubing and the outer casing as an added measure of security against a leak.

Those and other new regulations led the Council to conclude that gas operations can be managed safely in California, said Jens Birkholzer, a scientist from Lawrence Berkeley National Laboratory who co-chaired the study.

The report says earthquakes, fire, landslides and even tsunami post risks to the gas fields in the Los Angeles area and to surrounding populations.

However, even though the Aliso gas well blowout affected the health of what the report described as “tens of thousands of people,” the council report said underground natural gas storage is needed in California least the next few decades.

The state's debate over gas storage safety and viability does not end with this report. The Public Utilities Commission, which regulates investor-owned utilities, has a similar inquiry underway.

The report also found that underground storage fields account for about 8 percent of the greenhouse gas emissions connected to the natural gas sector in California. Of those gas fields, Southern California Gas’ fields are responsible for a majority of emissions.

"We conclude that [underground gas storage]-related methane emissions appear to be a small part of both California’s methane and total GHG emission inventories,” the report said.

Even after the ruptured well known as SS-25 was plugged at Aliso Canyon, that gas field still accounts for about 16 percent of the greenhouse gases that come from underground gas storage fields. SoCal Gas' Honor Ranch storage field outside Santa Clarita is responsible for another 45 percent of the greenhouse gases from gas storage fields.

Sen. Henry Stern, who represents the Porter Ranch area, said the study highlighted the lack of information the state has about what chemicals are being injected and withdrawn with the gas.

He wrote,"1.5 million Californians live near giant gas fields and they deserve to know what chemicals are being pumped underground, and if the companies operating these gas fields are doing so safely. The public cannot just rely on self-policing."

Researchers were unable to get data about the constituent elements of the methane stored at each of the state's 12 underground storage fields because the companies that operate those fields do not measure those substances, said Birkholzer. Some of those elements can be toxic, he said. A recommendation of the study is that samples of the methane be tested.

Stern said he was willing to sponsor a new law to require testing if state regulators do not undertake the testing.

The storage fields operated by Southern California Gas are unique in the state in that they inject natural gas into underground rock formations that previously held oil. All the other gas storage fields in the state are fields that originally held natural gas, which were depleted and then refilled with new supplies of gas. The methane coming from a depleted oil field could have different constituent elements than gas coming from a depleted gas field, Birkholzer said.

SoCal Gas, owner of the Aliso Canyon field and three other fields, welcomed the report's conclusion that natural gas stored underground remains a necessary part of the state's energy mix. The company fills its gas reservoirs in the summer when gas is cheaper, and withdraws it in the winter when the cost is higher and other users on the East Coast are competing for the limited supply.

"Potential risks associated with underground storage can be managed, and SoCal Gas has already introduced industry-leading safety practices that state regulators and independent experts have referred to as the most comprehensive in the nation," SoCal Gas spokesman Chris Gilbride said in an email statement.

The company's storage capacity could be used for other products, including methane created from food and dairy waste, or hydrogen, Gilbride said.

"SoCalGas has been a leader in promoting the development and use of renewable natural gas and is committed to being a part an integrated plan to achieving future long-term energy reliability while meeting the state’s aggressive greenhouse gas emissions goals.”

“The report confirms why California must transition off of gas to renewable energy, and why Aliso Canyon must be shut down now, said Alexandra Nagy, senior organizer for Food & Water Watch, in an email statement. Nagy has been coordinating some of the local activists who want the Aliso Canyon storage field closed.

"Every day thousands of Los Angeles residents are continually sickened by continued operations at the Aliso Canyon storage facility," she said. "Aliso Canyon must be the first facility to be decommissioned in a new era of getting off fossil fuel infrastructure and transitioning the state to 100 percent renewable energy.”

Correction: An earlier version of this story mischaracterized the amount of methane that underground gas storage facilities contribute to California's overall greenhouse gas emissions. The story has been corrected.